1. Field of the Invention
The invention is related to pad devices for industrial slings that are designed to lift or pull heavy loads (e.g., machinery, structural members, concrete objects, etc.), and more particularly to protective pad devices which protect such slings from the edges or corners of these loads (e.g., shipping container edges, etc.)
2. Background Description
Industrial slings are used to lift and move heavy objects. They are used at shipping yards, construction sites, loading areas, and in a wide variety of other applications. Industrial slings have been made from chains and wire cables in the past; however, many of today's slings (e.g., those employed in the last two decades) are made of tough and durable fibers, and they resemble a strap which is wrapped around the load for lifting and/or pulling operations. These fiber slings can be subject to catastrophic failure if they are cut, subjected to abrasion, or are otherwise worn down. This type of damage can occur when the object being lifted or pulled has a sharp corner or edge, and the sling is held taught against the edge during the lifting or pulling operation.
As discussed in U.S. Pat. No. 7,744,138 to St. Germain, which is herein incorporated by reference, there are a number of ways the problem of sling degradation and failure can be addressed. For example, the object to be lifted (e.g., a pipe section, a cargo container, structural steel, etc.) can be fabricated with eye bolts or hooks, and the sling would be slipped through the eye bolts or hooks for lifting operations. After moving the object, the eye bolts or hooks could be removed. Another example is to manufacture protectors from angular pieces of cardboard that abut against edges of the objects to be moved (e.g., U.S. Pat. No. 6,470,637 to Gratz describes molded pulp corner protector to protect windows during shipment).
U.S. Pat. No. 7,744,138 to St. Germain, as well as the Cornermax™ sold by Slingmax for many years prior to the filing of the St. Germain patent, describe corner pads used with industrial slings. These pads form a tunnel between load edge and the pad so that the pad as well as the underlying sling are protected from contacting the load edge during lifting or pulling. However, these corner pads are somewhat cumbersome as they require two pairs of mating straps to be looped around the sling and joined together by Velcro® (hook and loop connector).